Citing the threat of plastic, 3D-printed firearms, U.S. Rep. Steve Israel, D-N.Y., held a press conference this weekend calling for the renewal of the Undetectable Firearms Act. The act was originally conceived in 1988 in response to the Glock 17, a handgun with some components made from plastic composites.

The law has been renewed several times since its inception, most recently in 2003. It's currently due to expire in December 2013.

For gun rights advocates, the Undetectable Firearms Act comes across as legislative hand-wringing. Others find the law to be an example of security theatrics and a threat to the growing 3D-printing market. In the interest of sorting out the facts, CNET has put together this FAQ:

Q: What are the specifics of the Undetectable Firearms Act?
The meat of the law makes it a federal offense to "manufacture, import, sell, ship, deliver, possess, transfer, or receive" a firearm capable of defeating airport metal detection. It requires that any firearm, minus the stock, grips, and magazine, have an X-ray detection signature no less than that of a calibration sample containing 3.7 ounces of stainless steel.

The law also prohibits you from making or selling a firearm that "does not generate an [X-ray] image that accurately depicts the shape of the component." In other words, it's a federal crime to make and sell a gun that looks like something else to an airport X-ray scanner.

Q: Do plastic guns exist?
It's easy to fall down the rabbit hole on this one. Search "non-metal gun" and the results turn up a mix of alleged designs over the years, from reported CIA research to Anarchist Cookbook-style zip gun plans. Confirming the existence of an entirely plastic firearm is even more elusive.

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Without diverting too far down this path (the Straight Dope has a fun read on the topic), let's assume that making an undetectable firearm of some variety is not wholly impossible, be it the product of a well-funded research lab or some desperate tinkerer with no care for accuracy, reliability, or his own well-being.

Even if we do allow that undetectable firearms exist, there is no evidence to suggest that they are a common problem for U.S. law enforcement.

Q: So there's no such thing as a 3D-printable gun?
To public knowledge, no. Michael "Haveblue" Guslick has had the most success with this idea, designing and printing a component for the AR15 sport rifle known as the lower receiver. He says he fired almost 100 rounds from his design in a test.

During his press conference, Rep. Israel cited a recent firing test of the Wiki Weapon. That project is the would-be product of a group called Defense Distributed, whose stated aim is to disrupt the concept and mechanisms of firearms regulation. They hope to achieve their goals by designing and distributing the plans for a functioning plastic gun that anyone can make with a $500 3D printer.

You can read all about Defense Distributed on the group's Web site. Their project received only the necessary funding in the past few months, and they've hit a few snags along the way, from a revocation of a leased 3D printer to a friendly chat with their local ATF field office.

The Defense Distributed firing test that Israel referred to was in fact only a review of Guslick's existing design. Defense Distributed might have captured some worthwhile data from that test, but it has not yet shown evidence of a 3D-printable gun design beyond what Guslick came up with back in August.

Q: If Defense Distributed does develop an all-plastic, 3D-printable gun, wouldn't it be illegal under this act?
The law makes certain exceptions for the military and the CIA, and also provides some room for manufacturers that want to test whether a certain design falls within the requirements of the law.

Perhaps Defense Distributed can find some loophole in those exemptions, but otherwise it's hard to imagine how the group would not be in violation. That said, Defense Distributed spokesman Cody Wilson was the first person to make me aware of the law's existence, so the group certainly knows it's a hurdle they will have to deal with.[[Update: Wilson contacted me with a clarification. "Defense Distributed is now a public interest publisher of IP. At the end of October, our sister operation applied to become a firearms manufacturer. The Undetectable Firearms Act exempts manufacturers. The ban will not affect our operations in the least."]]

Q: If you can't print a plastic gun yet, isn't renewing this law just an example of security theater or legislative grandstanding?
The Undetectable Firearms Act has had its critics since it was enacted in 1988, largely because of the general belief that no one has ever made a functional gun that can sneak by an airport X-ray scanner.

U.S. House Rep. Steve Israel

Those in support of the law would argue, among other things, that even if no undetectable guns exist, it can act as a deterrent to the development of such a design. They would also say that it gives the federal government a forward-looking enforcement tool in the event that someone does come up with an undetectable firearm, 3D-printed or otherwise.

In calling to renew the law, Israel riled 3D-printing enthusiasts by using Defense Distributed as an example. Comments from Suffolk County Police Chief James Burke, who was present at the press conference, also caused some controversy. Burke was quoted by Meetthe112th.com as saying, "With the prices of these printers under $1,000, I think anyone can imagine the rise of an amateur gun maker in our community."

Q: Is renewing the Act really just a stealth attempt to regulate 3D printing?
Among other 3D-printing enthusiasts who found the press conference troubling, Boing Boing's Cory Doctorow voiced his concerns with Burke's and Israel's comments in a blog post:

However, what Rep. Israel doesn't say is how he hopes to accomplish his goal. Firmware locks for 3D printers? A DMCA-like takedown regime for 3D shapefiles that can be used to generate plastic firearms (or parts of plastic firearms?). A mandate on 3D printer manufacturers to somehow magically make it impossible for their products to print out gun-parts?

Doctorow seems to be reacting to the idea that renewing the Undetectable Firearms Act also means regulating 3D-printing technology. Israel and Burke hold Defense Distributed and 3D printing out as scary examples, and the law does establish legal consequences if you're found to have used any tools or mechanism to make an undetectable firearm. In it's current language, though, the Undetectable Firearms Act contains nothing specific to the pro-active regulation of 3D printing, or any other manufacturing process.

Israel's spokesperson also confirmed to me that "there are no technical aspects of the law that we're trying to change."

This is not to say that a politician might not one day take up the cause of regulating 3D printers or the distribution of printable design files. In that event, Israel and Chief Burke using it as a bugaboo here might make such regulations easier for voters to stomach. But the Undetectable Firearms Act as it's currently written places no pro-active restrictions 3D printing.